MS OneDrive file storage on a MacBook Pro
Is there a recommended way to migrate files from MicroSoft OneDrive to Apple iCloud?
Provided that you have installed the OneDrive application on your MacBook Pro with all the files synced between your Mac and the OneDrive server, and that you have signed into iCloud on your Mac then all you need to do is to locate the files in your OneDrive folder in Finder then drag and drop them into your iCloud folder.
This will move the files from OneDrive to iCloud, which is to say it will remove them from OneDrive in the process.